I've never used the survival version of the pocket chainsaw, but I've used a high limb chainsaw quite often. the one that I use the most has a 4 foot chainsaw portion attached to two 150' lengths of ELS cord (Extra Low Stretch). You get that sucker moving back and forth on a branch and it goes through like butter. I've also used the 4 foot saw to take down a 2 foot diameter tree by myself (took a while, but it did it) and a 3 foot diameter tree with a buddy on the other end of the saw.
I've contemplated picking up one of the 2 foot versions to keep in the backpack, but just haven't gotten around to it, but the 4 footer does ride in the car all the time, along with quite a few other tools.
I'll also second RickJ and and Cliff RE the Coghlans Sierra Saw and Felco Pruning saws(blades are made by the same company, IIRC). The Felcos are generally a little more comfortable, if slightly higher priced.
Now if you're expecting to be cutting down a lot of stuff, and you don't want the weight of a chainsaw, look into a Nicholson "Silver Flash" pruning saw. It's about a pound and a half(3 lbs with good, heavy duty sheath), 26" blade, and would cost about $50(US, I notice you're in Canada). Other than a full size felling saw, I haven't found anything non-motorized that cuts better than a Silver Flash, and I've spent a lot of time trimming trees.
Rick, the reason the coghlans and related saws cut on the pull stroke is that they were originally desgined for arborist work, and when you're 50+ feet off the ground in a tree, a push stroke cut winds up giving you a lot more motion, which means it'd be easier to fall. Also, the pull cut saws will bind less, as you can exert more force on them without having to worry about bending the blade.
When it comes to knives to accompany whatever saw you choose, what I have with me depends on where I'm going. I think I own most of the knives mentioned in this thread (Golok, BK7, Camp Tramp, Pukko, Himalayan Imports Khukri, Multitools and lots o SAKs) my personal favorite load out for backcountry camping would be my Corona folding pruning saw(like the Sierra saw, but 10" blade and a wood handle), the Camp Tramp, the everpresent SAK, and then there's a Gerber Multitool and a Pukko in my backpack. I like my Golok, but in my area, it gets more use trimming trees and doing gardening work. Of course, if I needed to break trail through brambles and such the Golok is definitely going along with me, as it's long and light and can be swung all day if necessary, whereas the BK7, Camp tramp, and even the Khukri would leave my arm begging for mercy and would be nowhere near as fast. What works best all depends on what you're going to do.
I don't think you can go wrong with the Camp Tramp or the BK7(Tramp is much more comfy in my hands and sharpens up easier for me), and others have reviewed the U/S saw very highly.
TC